Electric motor or generator.



H. A. BALGOIVIE.

ELECTRIC MOTOR OR GENERATOR.

APPLICATION FILED OCT- 24.1910- Patented June I, 1915.

menses UNITED STATES PATENT OFFICE.

HERBERT A. BALCOME, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE HOLTZER- CABOT ELECTRIC COMPANY,

MASSACHUSETTS. I

specification of Letters .Patent.

0F BROOKLINE, MASSACHUSETTS, A .GORPQRATION OF ELEGTRIC MOTOR GB GENERATQR.

Patented June 1 1915,

I application filed @ctclccr 24, 19-16 Serial No, 585,630.

To all? whom may concern 4 Be it known that l, HERBERT A. Benson's, Ia citizen of the United States, residing VJ est Ronlcury, Boston, in the county of Suffolk ancl tats oi lilassacllusetts, have invented certain new useful improve ments in ectricll lotors or Generators; do heresy cieclare the following to be it full, clear, exact description oi the invention, such as will enable otliers skilled in the art to which it annei -tains to malice and use the same The present inive iticn relates to electric i tors generators, ancl more particularly to dustor moisture-proof of such machines,

The operation of a lectric motor or orator results in-cer' in losses energy which appesrs in. the form of heat is "Well lmown I 'lieat is allowed to become-excessive it affects nelialoility of the machine clue to the deterioration of the insulating" substances used Such laein' the case, it isessentiel that the temperature of a generator or meter-be kept Within such linithet insulating materiel will not be so afrectec'l. to in ure the macnine. Artiiiciel cooling i commonly resorted to to keep down the temperature, CO'llSQl the nieclnne i air passages theretlirougli toallc-W r constant circulation to carry away the heat, However, when such conductors must loe increased to allow for a comparatively low current density therein, thus increasing the size of the machine. is rease in size means an increase ls l i met cost and in cost ofrepairs, renders the machine so lcullry tnct is-not suitable for the Work which it is expected to perform, as, for example, where it is desirecl to mount a motor upon a grinding or polishing machine. The inclosinsi frame must of necessity be strong enough to support the parts of the machine attachecl to it, and also to afford protection to them, especially Where such' machines are to receive rough usage. In such machines the heat must travel a comparstively long distance from the coils, Where it is genersteel, the inside of the inclosing case snil then pass through this comparatively thick case loefore it can lee dissipated alrcm the outer surface thereof 1e object oi the present invention is the production of a dust-proof or moistureproof dynamo-electric machine from which the heat maybe rea ily eiissipetc f itli this object ieW, the present ll": vention. contemplates a clynamo-electric inacliine liaising an open outer supporting firanie, and a closed inner casing which surrounds those Working parts of the machine which it is desired; to protect ircin dust or moisture and. which inner casing is con structerl thin liea conducting material to allon the heat to readily pass therethrough and be clissrpateel the outside air Winch has free access to its surface. Since this inner casing surrcunis only the Working parm the machine, the heat generatecl therein has but a comparatively short path in reaching the inner casing, which, since it has no supporting; function, may be of very thin materiel for. the easy conduction of locate I The outer surface of the inner casing is "l i tfi ll lo preleraoy coo ccl er n v12 y y a scream 0L sir drawn between it and the outer casing or frame of the machine. This circulation or air 'Wlll cool and greatly increase the sillcienc -y of the inner casing: in ollssipating heat,

and Will else cool such parts or" the interior of the machine as are not inclosecl Within-the inner casing and which Will have more or less neat conducted to them from the parts preferably made so that the-air circulation shall be increased simultaneously with the speed of the machine.

With the aboveiobjects in View, the present invention consists in the electric motor or generator hereinafter described, and particularly defined in the claims.

Tn the drawings, Figure 1 is a side view, taken partly in section, of a motor embodying the preferred form of the invention; Fig. 2 is an end elevation of the motor, and Fig. 3 is a section on the line 33, Fig. 1.

The illustrated embodiment of the invention is described as follows The frame of the machine consists of a supporting drum 1 to the interior of which is secured the field magnet 19.. The pole pieces 2 are formed by inwardly projecting poles on a ring of the field magnet 19.. The ring is supported by a number of inwardly projecting fiangesQO on the drum 1. The ring and the inwardly projecting supporting flanges 20 form a construction which is old and well-known and which constitutes no part of the present invention The drum 1 is provided with a number of air passages 3 through it. Secured to each end of the drum are end bearing caps i in which is journaled at 5 the driving shaft 6 which carries the armature 7 and its commutator 8. The outer end of the end caps d are provided with a number of air passages 9. In each end bearing cap is a diaphragm 10 through which the shaft 6 passes in a dust-proof bearing of felt or other suitable packing. Each diaphragm 10 is provided around its periphery with a number of ope ings 11 for the passage of air. Inside of the region -of the openings 11 ieach diaphragm is formed with an annular flange 12 which engages and forms a dust-joint with the end of a thin metal drum 13, suitably secured to the frame 1. The drums 13 are secured in a dust-proof manner to the sides of the ring '46 the field magnet 19. Each drum is slipped over an annular collar 22 of L-shaped cross section which is securedon the side of the field magnet 19 by means of bolts 24. When the motor is assembled, the field magnet the two diaphragms 10 and; drums 13 form a dust-proof casing covering the armature and field coils which constitute the parts of the machine which it is desired to protect from dust or moisture. The diaphragms 10 and drums 13, which form the inner coverings, are constructed from sheet metal made as thin as practicable to allow for the easy conduction of heat therethrough. The end caps 4 are made of such dimensions as will allow sufiicient roomi therein for air imellers 15 which are mounted uponthe driv The air impellers 15 are shown as fans and may be of either the centrifugal type or the propeller type, but preferably a combination of the two. When the shaft isrotated the fans 15 draw air through the openings 9 and blow it over the diaphragms 10 and drums 13, after which it passes out through the openings 3. The circulation of the air is indicated by arrows in Fig. 1. The outer parts of the field magnet, as shown in Fig. 1, are exposed to the circulation ofthe air fiowing'into the drum 1 from both ends and passing out through the openings 3. To permit access to the brushes and brush-holders,

sliding doors 16 are placed upon the drum surrounding the commutator These doors are of course made dust-tight and preferably come opposite openings 17 through the end caps which allow easy accessto the brushes and commutator. The openings 17 are closed by rough casting covers which are not necessarily dust-tight.

The armature is. provided with air con= ducting ducts which will cause a forced circulation of air through the armature to carry the air from the heated armature.

passing over the exposed parts of the field magnet which are external. to the dust-proof casing also helps to carry away the heat which is communicated 'to the field magnet cores from their coils.

The present invention is not limited to the illustrated embodiment, but is equally applicable to all other forms of dynamo electric v machinery which 7 it is desired to protect against either dust or moisture, of both. Where, in thecforegoing description of the invention, or in the following claims, the word dust-proof is used, it is intended to define a construction which is substantially i dustor moisture-proof or is both dustand moisture-proof. In" the claims the words field and armature are not intended to limit the invention to machines in which the field is stationary and the armature ro tary.

Having thus described the invention, what is claimed is: A a

1. An electric motor or generatorhaving, in combination, an outer supporting frame, a stator provided with -pole pieces and field coils for the armature she and thin-walled heat-conducting inner coverings which, in conjunction with the stator and the shaft, inclose the inner ends of the pole pieces, the annature and the field coils, substantlally as described.-

ipole pieces, an armature, an

I 2., An electric motor or generator leaving, in combination, an. outer supporting frame a stator providml with pole pieces and field coils fer the pole pieces, an armature, an si'mecuie shaft thin-Walled heat-conducting inner coverings which, in conjunction with the sealer and the shell; inclose the inner ends of the pole pieces, the armature anal lZhG field ccils endhlowing means for causing a cooling circulation of air Within the supporting imme 2H1& over the cuter surfaces of the inner coverings, substantially as clesciilcecl,

3: An electric motor or generator having", in comb-i scion, an eucei" supporting fi sme, an ei meiure supportecl by said frame, a (lust-proof casing heaving thin-Walled lieekcoiieluc bing portions for covering retailing eec a field magnet and armature supportecl a.

thereby, e, (lust-proof casing having lllllll Walled heat-conducting portionsfor cover ing rotating parts the motor or genereicom encl blowing means for causing a cooling ci1c= eulebiom of air ever else cuter surface of co eeing means, sulis' csntielly es desciibeclo Roy T. WEZWAQBS Docems GAERNSQ 

